The invention relates to a method of and to an apparatus for making pads of coherent sheets, and more particularly to improvements in a method of and an apparatus for making so-called post-it (trademark) self-sticking note pads wherein a portion of each next-following sheet in a stack of sheets adheres to a layer of adhesive at the rear side of the preceding sheet.
Sheets which are detached from self-sticking note pads can be used for attachment to other sheets, to metallic surfaces or to any other smooth surfaces and can be detached and reattached a number of times. The adhesive reduces the likelihood of unintentional detachment and/or unintentional shifting of the sheets. Moreover, there is no need to maintain a supply of paper clips, and a sheet can be detached without leaving any traces on the surface from which it was removed.
In accordance with heretofore known proposals to make self-sticking note pads, a paper web is drawn from a large roll and one of its sides is coated with adhesive in a suitable applicator, for example, an applicator which is a modified screen printing machine. The thus coated web is again convoluted to form a roll and the roll is transferred to a severing station where the web is withdrawn and is subdivided into a series of sections which are accumulated to form stacks or reams. This often creates serious problems because one side of each section carries a coating of adhesive so that the sections cannot be readily shifted or shuffled into stacks. The situation is aggravated due to the fact that, as a rule, the sections which leave the severing station form a so-called scalloped stream of partially overlapping sheets.
Layers of large-size sections are delivered to a further station where several cutting machines with integrated cutting sequences operate to subdivide the layers into pads of desired size. The pads are transported to a discrete packing station to be draped into cellophane or foil, either individually or in groups of two or more.
The just discussed discontinuous operation involves a number of splintered discrete operations which contributes significantly to the cost of the products, especially because the operation must be monitored and regulated by a relatively large number of workers. Moreover, the space requirements of the plant are substantial and the initial as well as maintenance cost for the production line is very high.